Seclusion Game Engine is described as 'The Seclusion Game Engine ("SGE", pronounced like "sage") is a general-purpose libre open source 2-D game engine for Python. It takes care of several details for you so you can focus on the game itself'. There are eight alternatives to Seclusion Game Engine for a variety of platforms, including Windows, Linux, Mac, FreeBSD and iPad. The best alternative is Godot Engine, which is both free and Open Source. Other great apps like Seclusion Game Engine are GDevelop (Free Personal, Open Source), LÖVE (Free, Open Source), PGE Project (Free, Open Source) and Pygame (Free, Open Source).
Godot is a fully featured, open source, MIT licensed game engine. It focuses on having great tools, and a visual oriented workflow that can export to PC, Mobile and Web platforms. It is a cross-platform 2D and 3D game engine and game development IDE.
GDevelop is an open-source game making software designed to be used by everyone. Any kind of 2D games can be created with it and no programming skills are required to get started. Logic of games are made using visual events.
Pygame is a set of Python modules designed for writing video games. Pygame adds functionality on top of the excellent SDL library. This allows you to create fully featured games and multimedia programs in the python language.
A refreshingly simple data-driven game engine built in Rust. Free and Open Source Forever! Data Driven All engine and game logic uses Bevy ECS, a custom Entity Component System - Fast: Massively Parallel and Cache-Friendly.
Flax Engine is claimed the most agile game engine. It's open source, cross-platform and it lets you write scripts in C++ and C# seamlessly. Also focused on lightweight development. A true game changer.
A game-engine fully integrated in Blender UPBGE is an open-source, 3D game engine forked from the old Blender Game Engine and deployed with Blender itself. This unified workflow is its main strength, as you can make your game from start to finish without leaving Blender.